DES MOINES, Iowa -- A man allegedly called police to tell them he made an IED while sitting at an Iowa sushi restaurant, which officials say could have killed customers if it went off.

It happened around 6:40 p.m. Tuesday, January 15 at Japanese restaurant called Akebono in Des Moines. The owner of the restaurant said he had no idea what was going on.

"Cops talked to my host and said somebody called 911 over here, talking about a bomb," Nam Tran, the restaurant's owner, told WHO-TV. "And the host asked me, and said not that we know of. We don't know nothing about (it), so after that a few cops come in and I asked, "Can I help you? What's going on here?" And, he said, "Well, somebody called over here and said, you know, a bomb over here. I said not that I know of."

40-year-old Ivory Washington called the police himself and told them he'd made an improvised explosive device while sitting in the restaurant. Washington described the explosive device to police as being fake, but police say in fact it was real.

"Obviously, you`re going to treat this thing like it's the real deal until you know something different," said Sergeant Paul Parizek, Public Information Officer for the Des Moines Police Department. "We were able to separate him from the device without incident, take him into custody and we got the bomb squad there. They did their diagnostic on this device and found out that it basically is a homemade hand grenade. It was legit. When they tested it to see if it would explode, it did."

Had the device gone off in the restaurant, it could have been deadly.

"They said anybody basically within about 25 feet of this would have been injured," said Parizek. "Somebody within a ten-foot radius, had it gone off, might have been killed."

Police said Washington was trying to make a point.

"He gave us a story where he is extremely frustrated with our world today," said Parizek. "And, believes that people that don’t take these types of threats seriously. So, he was going to make a point that he could sit somewhere and construct a device and hopefully somebody would call the police. He said that he attempted this in one of the suburbs and nobody cared. So, he got more frustrated, came downtown, sat there, built it while he was sitting in the restaurant and finally called the police on himself."

Washington is charged with possession of explosive or incendiary material with intent. He is being held on a $10,000 bond in the Polk County Jail.